/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.table.runtime.operators.sort;

import org.apache.flink.metrics.Gauge;
import org.apache.flink.runtime.memory.MemoryManager;
import org.apache.flink.streaming.api.operators.BoundedOneInput;
import org.apache.flink.streaming.api.operators.OneInputStreamOperator;
import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
import org.apache.flink.table.data.RowData;
import org.apache.flink.table.data.binary.BinaryRowData;
import org.apache.flink.table.runtime.generated.GeneratedNormalizedKeyComputer;
import org.apache.flink.table.runtime.generated.GeneratedRecordComparator;
import org.apache.flink.table.runtime.generated.NormalizedKeyComputer;
import org.apache.flink.table.runtime.generated.RecordComparator;
import org.apache.flink.table.runtime.operators.TableStreamOperator;
import org.apache.flink.table.runtime.typeutils.AbstractRowDataSerializer;
import org.apache.flink.table.runtime.typeutils.BinaryRowDataSerializer;
import org.apache.flink.table.runtime.util.StreamRecordCollector;
import org.apache.flink.util.MutableObjectIterator;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/** Operator for batch sort. */
public class SortOperator extends TableStreamOperator<RowData>
        implements OneInputStreamOperator<RowData, RowData>, BoundedOneInput {

    private static final Logger LOG = LoggerFactory.getLogger(SortOperator.class);

    private GeneratedNormalizedKeyComputer gComputer;
    private GeneratedRecordComparator gComparator;

    private transient BinaryExternalSorter sorter;
    private transient StreamRecordCollector<RowData> collector;
    private transient BinaryRowDataSerializer binarySerializer;

    public SortOperator(
            GeneratedNormalizedKeyComputer gComputer, GeneratedRecordComparator gComparator) {
        this.gComputer = gComputer;
        this.gComparator = gComparator;
    }

    @Override
    public void open() throws Exception {
        super.open();
        LOG.info("Opening SortOperator");

        ClassLoader cl = getContainingTask().getUserCodeClassLoader();

        AbstractRowDataSerializer inputSerializer =
                (AbstractRowDataSerializer)
                        getOperatorConfig().getTypeSerializerIn1(getUserCodeClassloader());
        this.binarySerializer = new BinaryRowDataSerializer(inputSerializer.getArity());

        NormalizedKeyComputer computer = gComputer.newInstance(cl);
        RecordComparator comparator = gComparator.newInstance(cl);
        gComputer = null;
        gComparator = null;

        MemoryManager memManager = getContainingTask().getEnvironment().getMemoryManager();
        this.sorter =
                new BinaryExternalSorter(
                        this.getContainingTask(),
                        memManager,
                        computeMemorySize(),
                        this.getContainingTask().getEnvironment().getIOManager(),
                        inputSerializer,
                        binarySerializer,
                        computer,
                        comparator,
                        getContainingTask().getJobConfiguration());
        this.sorter.startThreads();

        collector = new StreamRecordCollector<>(output);

        // register the metrics.
        getMetricGroup().gauge("memoryUsedSizeInBytes", (Gauge<Long>) sorter::getUsedMemoryInBytes);
        getMetricGroup().gauge("numSpillFiles", (Gauge<Long>) sorter::getNumSpillFiles);
        getMetricGroup().gauge("spillInBytes", (Gauge<Long>) sorter::getSpillInBytes);
    }

    @Override
    public void processElement(StreamRecord<RowData> element) throws Exception {
        this.sorter.write(element.getValue());
    }

    @Override
    public void endInput() throws Exception {
        BinaryRowData row = binarySerializer.createInstance();
        MutableObjectIterator<BinaryRowData> iterator = sorter.getIterator();
        while ((row = iterator.next(row)) != null) {
            collector.collect(row);
        }
    }

    @Override
    public void close() throws Exception {
        LOG.info("Closing SortOperator");
        super.close();
        if (sorter != null) {
            sorter.close();
        }
    }
}
